1. Technical Field
The present invention relates to an electrophotographic image forming apparatus having a transfer material-gripping section and a transfer roller that transfers an image on an image carrier onto the transfer material and relates to an electrophotographic image forming method.
2. Related Art
In a wet type image forming apparatus using a liquid developer, because a surface of a transfer material, such as paper, facing a toner image is in contact with an intermediate transfer medium by being pressed thereon, the transfer material is often attached to the intermediate transfer medium after image transfer. Accordingly, in Japanese Patent No. 3,128,067, an image forming apparatus is proposed, in which air is blown to an anterior end of a transfer material after image transfer to separate the transfer material from a transfer roller.
On the other hand, with respect to an image forming apparatus using a dry developer, in JP-A-3-4241, an image forming apparatus is proposed, in which a toner image on a photoconductor is transferred onto a transfer material in a state in which an anterior end of the transfer material is gripped with a gripper of the transfer drum being in contact with the photoconductor by being pressed thereon. The transfer in a state in which the anterior end of the transfer material is gripped enables the transfer material to be easily separated from the photoconductor after image transfer. Furthermore, in JP-A-6-135613, an image forming apparatus is proposed, in which a transfer material-transporting belt having a plurality of suction holes transports a transfer material after image transfer while subjecting the transfer material to suction, and in which the transfer material is guided to a fixing section with a guide. The transfer material-transporting belt transports the transfer material while subjecting the material to suction, so that it is possible to achieve excellent transportability for the transfer material and to achieve excellent fixing.
Meanwhile, in the image forming apparatus disclosed in Japanese Patent No. 3,128,067, because air is merely blown to an anterior end of the transfer material, it is difficult to steadily separate the transfer material. Accordingly, it may be proposed that a technique for separating the transfer material at the anterior end thereof with the gripper, which is disclosed in JP-A-3-4241, is applied to the image forming apparatus using the liquid developer, which is disclosed in Japanese Patent No. 3,128,067. Furthermore, it may be proposed that the transfer material-transporting belt disclosed in JP-A-6-135613 is applied to the image forming apparatus disclosed in Japanese Patent No. 3,128,067. Unfortunately, in cases where the gripper grips the anterior end of the transfer material, the gripped portion of the transfer material is deformed into an undulating shape as shown in FIG. 8, and the transfer material is folded in a direction away from a surface onto which a toner image is transferred, resulting in a mark of the gripping being left behind. Consequently, the guide catches the anterior end of the transfer material transported with the transfer material-transporting belt, so that the transfer material may jam.
As a result, it is difficult to apply the technique for separating the transfer material, which is disclosed in JP-A-3-4241, and the technique for transporting the transfer material while subjecting the material to suction, which is disclosed in JP-A-6-135613, to the image forming apparatus disclosed in Japanese Patent No. 3,128,067 to achieve excellent fixing and to excellently form an image.